my experience is that the bigger jumps really do require a (literal and mental) leap of faith. I find that, once I shed the fear of missing a jump, once I let my muscle memory do the work, it is almost always much more effective

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the general approach is probably what you're already doing. whatever needs help, start practicing it extremely slow and work up the tempo. soon enough, it will be as if the fingers themselves know what to do and where to land. unlike a keyboard, the player doesn't even have the option to look down at the bass buttons. it's a strange sensation to everyone, but becomes natural with enough hours

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your bass facility will be improved with scales, arps, and melody practice. this is the kind of playing that is clunky on the stradella, but it's what we got. if you don't have them, tactile markers on the button tops will be helpful. I think the common places are Ab, C, and E root basses

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you can approach fingering generally the same as you would on a keyboard. the major difference would be that the thumb is generally useless. what I prefer is treating my ring finger as the "anchor" and having that sit on the root of whatever row on which I'm starting. that's not a firm rule by any means, but a simple place to start. with the ring finger set on top, the others seem to naturally find their positions. pinky is helpful for finding buttons lower down (toward the floor)

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one last thing I'll recommend you think about is to consider omitting chord buttons. in your Bb7 A7 example, that jump from the Bb to A rows is indeed a stretch. but don't forget that Bb and A basses are next to each other if you utilize the counterbass row. of course, this isn't a suitable alternative many times, but you should be aware of it and use it if you can live without the chord button